Utilisation of pre-exposure prophylaxis (PrEP) for HIV prevention in the Australian general practice setting: a longitudinal observational study

Background: Pre-exposure prophylaxis (PrEP) became available through the Australian Pharmaceutical Benefits Scheme (PBS) on 1 April 2018 for HIV infection prevention in patients ≥18 years at medium-to-high HIV risk. The aims were to investigate PrEP utilisation in general practice since PBS listing, and factors associated with discontinuation. Methods: This longitudinal study included patients aged 18-74 years attending general practices participating in MedicineInsight, a large-scale national primary care database of deidentified electronic health records, between October 2017 and September 2019. Results: PrEP utilisation increased 10-fold following PBS listing. On average, patients had 9.7 PrEP prescriptions per year; a medication possession ratio of 80.8%. Of 1552 patients prescribed PrEP from April 2018, most were male (98.3%), aged 18-39 years (59.3%), resided in major cities (86.7%) and in the two most socioeconomically advantaged quintiles (70.0%). Almost half (49.1%) of the patients were identified as new to PrEP. At study end, 65.1% were on active PrEP (16.5%, of whom had non-continuous use), 19.2% had discontinued PrEP and 15.7% were lost to follow up. Patients who discontinued were more likely to attend low rather than high PrEP caseload practices (adjusted odds ratio [aOR] 1.7; 95% CI: 1.0-2.8; P = 0.047). The odds of non-continuous therapy was 2.9-fold higher in patients with bipolar disorder (aOR 2.89; 95% CI: 1.10-7.6; P = 0.045). Conclusions: Following PBS listing, PrEP utilisation increased and stopping therapy was associated with attending low caseload practices. General practice education, particularly among low caseload practices, could help address these disparities.